For a time, oxygen was commercially produced by the Brin process which is completely disclosed in U.S. Pat. No. 432,815. In the Brin process, beds of barium oxide particles are heated in a chamber to a temperature of between 700.degree.-750.degree. C. This temperature is maintained substantially constant and clean, dry air under pressure is passed through the chamber. The barium oxide reacts with the oxygen in the air to form barium peroxide while nitrogen is released as a by-product. After a period of time, the flow of the pressurized air is interrupted and the chamber is connected to a source of vacuum. As the gas in the chamber is evacuated, the barium peroxide releases the earlier acquired oxygen as it reverts back to barium oxide. The released oxygen is captured and communicated to a storage container for later use.
From experimentation, it was determined that the efficiency of the Brin process could be increased if the temperature of the barium oxide particles could be maintained at a constant temperature. The reaction between oxygen in the air and the barium oxide increases with temperature and reaches a maximum near the melting point of the barium oxide. Unfortunately, maintaining the temperature of the chamber at a constant temperature requires sophisticated heaters to prevent fluctuation in the chamber temperature since the barium oxide particles are alternately being subjected to air under pressure from outside the chamber and vacuum and also since the heat of reaction removes heat from and supplies heat to the barium oxide particles. In addition, the barium oxide particles located nearer the heaters receive the greatest heat while the barium oxide particles away from the heater are relatively cooler. In an effort to heat the barium oxide particles farthest away from the heaters, the temperature of the barium oxide particles adjacent the heater approach the melting temperature. Unfortunately, the heat generated through the reaction of air and the barium oxide and the chamber temperature is additive, and at time sufficient to cause the barium oxide particles to melt and fuse into a larger mass. This is not too serious a problem during the reaction part of the process since the pressure of the air flowing through the chamber can be increased to maintain uniform flow through the bed. However, channels and cracks form in the bed of barium oxide particles during the oxygen evacuation part of the cycle resulting in deterioration of the barium oxide beds since the air flow thereafter is not uniform.